The north London club confirmed on their website on Monday morning that Lukasz Fabianski will take over between the posts with Almunia having hurt his elbow when he gave away a penalty in Saturday's 3-2 Premier League home defeat to West Brom.
"We have Manual Almunia out," said manager Arsene Wenger. "He has a problem with his elbow. He caught it when he made the penalty on Saturday."
The Frenchman insisted he had no plans to drop Almunia had it not been for the injury.
"[The goalkeeper] is always the easy target, the easy scapegoat," he said. "But we win together and we lose together even if people think he made a mistake on the second goal."
Wenger will decide during training whether full-back Kieran Gibbs can board the plane for Serbia as he continues his recovery from the badly bruised foot he suffered in the Carling Cup win at Tottenham last Tuesday.
"Kieran Gibbs has a test in training today," Wenger added.